As the cross-Channel ferry captured the Kent coast in its sights, Richard Fearnside told his fiancée he was going up on deck for a cigarette.

The couple – engaged for just five months – were returning from a 10-day break in the south of France, where Richard had celebrated his 30th birthday.

But as the ship pulled into the Port of Dover at 1am, Richard had not returned.

His fiancée watched as passenger after passenger disembarked from the Pride of Kent, with still no sign of her husband-to-be.

Frantic with worry, she alerted ferry staff and triggered a desperate – and ultimately hopeless – search for Richard.

Fifteen miles away, at her home in Clare Road, Whitstable, Richard’s mother, Marianne, was woken by a telephone call.

It was her future daughter-in-law.

“She told me Richard had gone for a cigarette and disappeared,” Marianne recalls.

“She said she had watched him go up on deck and would regret that for the rest of her life.

“I couldn’t take it seriously or believe that it had happened. I thought there must have been some mistake, but there wasn’t.”

Panicked, Marianne and her husband Bob raced to the port, where a helicopter circled overhead, fanning its searchlight on the water below.

VIDEO: Marianne is urging the public for help. Josie Hannett reports

It was joined by a Royal Navy ship and coastguard and lifeboat crews, who scoured the seas for five hours, clinging to hope that if Richard was in the water he had survived the fall and 10-degree temperatures.

But as daylight came, there was still no trace of him.

“We almost expected him to walk in the front door, but it gradually became clear that he must have gone overboard,” Marianne said.

“They called the search off after five hours and said nobody could survive in the water for that long. We were all in shock.”

Police detectives – led by DS Richard Lown and DI Andy Bidmead – checked CCTV at the Port of Dover to see if Richard had got off the ferry, which had sailed from Calais at 11pm.

Cameras protecting the ship’s duty-free shop captured Richard onboard, but there was no evidence revealing how – or if – he had left.

The ferry was searched and Kent Police liaised with their counterparts in Calais, even working on a theory that Richard may have stayed on the ship and returned to France.

“Obviously you have to be open-minded,” DI Bidmead said, looking back at the case in a meeting room at Canterbury police station.

“We were of the view that if he wanted to go back to France, ferries are big enough places to hide.”

Such an elaborate stunt would have drawn comparisons to John Darwin, who infamously faked his own death in a canoe accident to start a new life in Panama.

But, after checks of Richard’s phone and bank records, the theory was quickly ruled out by investigators.

“If you want to disappear off the face of the earth like Mr Darwin you’ve got to have resources behind you and plans in place, whereas there was nothing to suggest that at all,” said DC Lown.

“Sometimes people get caught in a TV fantasy filmworld,” DI Bidmead added.

“If Richard Fearnside is still alive, it would be something like that, but it is so unlikely. The strongest hypothesis has got to be that unfortunately he is no longer with us.”

In the days and weeks after his disappearance, and with little hope of him being found alive, Richard’s family expected his body to wash up on the Kent coast.

“We kept waiting for that to happen, and dreading it happening,” Marianne said.

“You have so many different thoughts when it’s your child that goes – you never expect it. There’s a madness about it all”

“It’s very mixed feelings. You dread it, but you think if it did happen, then you would know. But you still don’t want there to be a body of your child.”

With no CCTV on the passenger deck, police were unable to piece together what were likely to have been Richard’s final moments.

Interviews with staff and passengers provided no evidence to suggest he had been pushed, and DI Bidmead says they were given a “clear steer that somebody couldn’t just fall over the side”.

He admits the investigation left him frustrated, but says the real sadness is with the family.

“Every part of you wants to go to them and say ‘we’ve resolved this, this is what’s happened, here is Richard and you can have closure’,” he says.

“But are we ever going to know what happened on the deck of the ship? No.

“Are we ever going to find Richard? I think that’s unlikely, but the one thing this job does teach you is never say never.”

Described as a “happy-go-lucky” child, Richard grew up in Whitstable but was schooled at Perry Court in Chartham, on the oustkirts of Canterbury.

He went on to study music technology at Canterbury College and later moved to the city, where he was living in a flat in Whitehall Bridge Road.

He and his fiancée – who we have agreed not to name – had been together for 18 months, with Richard proposing the Christmas before he disappeared.

The walls of his mother’s home are decorated with bright paintings, a nod to her former career as an art teacher at Faversham’s Queen Elizabeth’s grammar school.

But Marianne sees no colour in what has been the darkest of ordeals for her and her family. “You have so many different thoughts when it’s your child that goes – you never expect it,” she says. “There’s a madness about it all.”

The case remains open, but without a body Richard’s family have no final resting place for him and face four more years until a death certificate can be issued.

Marianne has planted a tree at Whitstable Castle in Richard’s name – a flowering cherry – which she visited with family and friends on Sunday for what would have been his 33rd birthday.

She says it took a year to accept he was dead, and concedes it is possible her son – who had previously experienced personal difficulties – had jumped from the ferry.

“Perhaps he did, but the point is, we just don’t know,” she says.

“You shouldn’t be able to do this split second thing, all over, all finished, and there’s no evidence. It’s not right.

“He had been driving for 14 hours, his first ferry was cancelled and he was probably exhausted. Who’s to say he didn’t fall? “How do we know somebody didn’t come up behind him?

“It’s all added up to the most awful happenings and, eventually, tragedy. There is no closure.”

Following Richard’s disappearance, Marianne wrote to ferry firm P&O, calling on it to install CCTV on all passenger decks, but she was told such a move was “impossible”.

She launched a petition to force them into action, drawing strength from the 100,000 people who have now supported her campaign.

But P&O – which says it carries 10 million passengers a year – retained its stance this week, even refusing to explain why it is “impossible” to cover all outside decks with CCTV.

The response came as little surprise to Marianne. “They have made it loud and clear that they don’t care,” she said.

“Somebody should not be able to simply disappear from a ferry and there be no evidence to show what happened to them.

“They should have a duty of care to their passengers, to ensure they are looking after them, that they know where they are, and that they’re safe from falling into the sea.

“It’s totally immoral. The attitude is that it’s only one person, but it’s my one person – it’s my son.”